After many years I now have this four volume masterpiece, translated as The Fortunate Aeon by Dharma Publishing.

Buddha replies to a general query about how to fulfill perfectly one's aspirations for buddhahood by saying:

There exists a samādhi that is known as Showing the Way of All Dharmas. The Bodhisattvas endowed with this samādhi come to obtain all of those wondrous qualities.

Those wondrous qualities are listed over many pages; in outline they are:

“In addition to this, they accomplish the twenty-one hundred paramitas; they also obtain the eighty-four thousand samādhis and the eighty-four thousand dhāranīs. They attain realization and become skillful in involving themselves in the activities of all sentient beings. They quickly become perfect Buddhas with genuine and unexcelled enlightenment.

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

“O Pramuditarāja, should you ask: ‘What is this samadhi
called Showing the Way of all Dharmas?’ It is as follows: It is
acting in accord with words of truth and speaking in accord
with such actions. It is purifying one’s body; purifying one’s
speech; purifying one’s mind. It is the desire to be of benefit. It
is having a loving mind and never giving up compassion;
it is never striving after desire, and always striving in the Dharma. It
is never exhausting one’s faith.

Many more pages giving these innate seeds of virtues are given.

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

Vast was their virtue, their minds unhindered; they were
without egocentric pride, and were endowed with patience.
Their virtue was like a great wave billowing, and they embraced
all the holy aspirations existing within the limitless array of the
Buddha-fields. They were continuously present in the samādhi
that recollects the Buddhas of the innumerable world systems,
and they were wise in the ways of communicating with the
countless Buddhas. They were skilled in quieting all forms of
emotional turmoil, karmic propensities, and destructive belief systems.
They were skilled in displaying by their samādhi
hundreds of thousands of playful actions.

From 1:5

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

The Bodhisattva Pramuditarāja then offered this request in
verse: “Many are gathered here of gods, men, yaksas, and
gandharvas, and others whose merit and wisdom are as limitless
as their devotion. We ask that the Moon of Teachers, the
Lightmaker, the Protector of the Worlds, give to us an ordered
exposition of the Bodhisattva’s activities, so that when they
have heard the qualities of the Bodhisattva’s wondrous path of
action, these hosts of earnestly aspiring living beings will strive
for enlightenment.

“Once faith has been generated in the great qualities of
enlightenment, we ask that you relate the full scope of these
qualities. You, of boundless renown, know our hearts — who
other than the Conqueror could be our witness? Both gods and
men are thirsty for these qualities of the Jina. Please tell us the
ways you wield the ten strengths. Tell us of your knowledge and
deeds, and the way of your beauty and renown. Tell us of the
arising of the qualities of enlightenment; tell us of the arising of
your wonderfully virtuous actions.

1:11

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

This samādhi is the inexhaustible Doctrine; it is difficult
for tīrthikas to understand; it has no resemblance to worldliness.
It goes beyond the dharmas of the Śrāvakas; it is not the
stage of enlightenment of the self-enlightened. It is truly
entering actual omniscience; it benefits the stream of sentient
beings; it is exhorting the Buddha to teach the truth, just as it is.

“This samādhi is fulfilling all spiritual commitments. It is
being skilled in communicating in different languages; liberating
all beings; basing one’s actions on sound understanding;
haring no desires concerning one’s body; having a perfectly
quiet mind; bringing satisfaction to those who are suffering;
praising those in bliss; and admonishing the heedless. It is
training those who would make effort.

“This samādhi is the clearing away of all regrets concerning
existence. It is not dwelling in the discrimination ‘sentient
being’ and not perceiving with object-oriented perception. It is
severing all grasping; destroying the marks of conditioned
existence; being unwavering in equanimity; always dwelling
upon pure awareness.

On the samādhi Showing the Way of All Dharmas; 1:27, 17

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

There are six paramitas of the world.
There are six paramitas focused on sentient beings.
There are six paramitas of devotion.
There are six paramitas of samsara.
There are six paramitas of the all-encompassing
fettering passions.
There are six paramitas of helping others.
There are six paramitas that take a position.
There are six paramitas of enlightenment.

Then after the list, Buddha gives details about each group of six. That makes up 350 or so pages of the 450 in volume one; ending up with around 2100 paramitas!

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

The six ‘purifying’ paramitas are the paramitas of those who
have not yet generated the Enlightened Mind of the Bodhisattva,
although their nature rejoices in giving, morality, patience,
effort, meditation, and wisdom for the sake of gaining
enlightenment. They have the aspiration for enlightenment,
without having expressed themselves concerning enlightenment
to any other sentient being or to the previous fully
accomplished and perfect Buddhas.

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

Nicholas Weeks wrote:There are over 300 categories of perfections listed, like these:

There are six paramitas of the world.
There are six paramitas focused on sentient beings.
There are six paramitas of devotion.
There are six paramitas of samsara.
There are six paramitas of the all-encompassing
fettering passions.
There are six paramitas of helping others.
There are six paramitas that take a position.
There are six paramitas of enlightenment.

Then after the list, Buddha gives details about each group of six. That makes up 350 or so pages of the 450 in volume one; ending up with around 2100 paramitas!

Too many for me to remember, I'm afraid. I might stick with (attempting!) the usual half-dozen.
More seriously, any such exhaustive list smacks of legalism or (mediaeval Christian) scholasticism. How can it be useful to the practitioner?

The Bodhisattva Pramuditaraja then said to the Lord
Buddha: “Lord, during my stay alone in retreat, when I entered
into deep absorption, I had the thought that all those who are
Bodhisattvas become perfected for the sake of enlightenment,
and such Bodhisattvas, by means of the paramitas performed
for the sake of enlightenment, amass the roots of virtue. And I
thought, Lord: Is a paramita something that benefits living
beings, or is a paramita something that helps one to gain
enlightenment? Is a paramita something impure, or is a
paramita something pure?

“My thoughts were like this. However that may be, would
the Lord please explain to us at length: In what paramitas do
Bodhisattvas truly develop, and in what paramitas do they
generate a firm grasp of the Dharma-way of the Bodhisattva —
the beginning, the middle, and through to the end? Would the
Lord please explain to us the practice of those of skillful means?
So that we may obtain an overflowing abundance of the highest
joy, I pray that the Lord grant us this extensive teaching.”

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

Another sample of teaching about one group of the six paramitas, from 1:134-35

What are the six paramitas that benefit oneself?

The paramita of giving ‘benefiting oneself’ is the giving of one
who is completely dedicated to achieving great transcendent
enjoyment.
The paramita of morality ‘benefiting oneself’ is the moral
practice that leads to birth as a man or god in the happy states
of existence.
The paramita of patience ‘benefiting oneself’ is the patience
that, due to the maturation of the attainment of patience,
causes one to have great beauty, a wonderful color, and great
glory and power.
The paramita of effort ‘benefiting oneself’ is the effort of actively
examining everything by one’s own efforts and never depending
on others for enlightenment.
The paramita of meditation ‘benefiting oneself’ is the meditation
of one who, because of the development of meditation,
does not come into a world between the kalpa of destruction
and the seven kalpas of generation.
The paramita of wisdom ‘benefiting oneself’ is the wisdom of
one who does not look to outside beliefs, of one whose actions
of body, speech, and mind follow the truth.

These are the six paramitas that benefit oneself.

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

At the end of volume one (477) where the last of paramita groups have been explained, this general statement by Buddha appears:

From these come the twenty-one hundred paramitas for
teaching the Dharma to all those who act with attachment; the
twenty-one hundred paramitas for teaching the Dharma to all
those who act in anger; and the twenty-one hundred paramitas
for teaching the Dharma to all those whose actions are a part of
each. Thus there are eight thousand four hundred paramitas.

Their samadhis are also eight thousand four hundred.
In their various forms of practice, there are also thousands
of other paramitas. As each of the hundreds of forms has
thousands of applications, one arrives at what is called “the
eighty-four thousand paramitas.” Those who accomplish the
84,000 samadhis of these paramitas are known as “those who
strive to benefit themselves.” The 84,000 dharanls are for
striving to benefit others. And, in order to gain omniscience,
there is the enlightenment of the Buddha.

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

VOLUME FOUR
The Extensive teaching on the Thousand Buddhas 1448
Buddha Pradlpa (973) — Buddha Roca (1004)
The First Thoughts of Enlightenment 1480
The Prophecies 1732

Lists of the Buddhas 1753
Glossary 1853
Index

And the Colophon:

The Aiya-bhadrakalpika-nama-mahayana-sutra is thus completed.
It was translated by the Indian Abbot Vidyakarasirhha
and the lo-tsa-ba Bande dPal-gyi-sbyangs, and later revised by
lo-tsa-ba Bande dPal-brtsegs.

Subham astu sarvaja gatam

This new edition [of the Bhadrakalpika-Sutra] was published in
the water male monkey year of the sixteenth rab-’byung [1932]
at Ku-se gSer-ljong dgon near sDe-dge lHun-grub stong in
Greater Tibet.

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

The paramita of giving ‘devoted to enlightenment’ is the giving
of one who, with firm adherence to vows and with the highest
resolve, dedicates everything to enlightenment.

The paramita of morality 'devoted to enlightenment’ is the
moral practice undergone without even thinking about it by
one who dedicates everything to enlightenment, conserving nothing.

The paramita of patience 'devoted to enlightenment’ is the
patience of one who has the firm wish to accept all suffering
patiently until the time of enlightenment.

The paramita of effort ‘devoted to enlightenment’ is the effort of
ceaseless practice, for kalpas beyond number, until the attainment of omniscience.

The paramita of meditation ‘devoted to enlightenment’ is the
paramita of meditation that distinguishes things nonreferentially.
It is the meditation of one who, in not distinguishing
things by the perception of existants, understands enlightenment.

The paramita of wisdom ‘devoted to enlightenment’ is the
wisdom of one who, until the time of enlightenment, distinguishes
that which is unthinkable from the inconceivable
nature of all existants, and comes to understand the nature of things just as they are.

These are called the six paramitas of devotion.

[pp 121-3]

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

This páramitá of giving is the giving of one who, for the sake of enlightenment, has patient conviction in the non-arising of all constituents of reality.
This páramitá of morality is the morality of those who do not focus on their own body or mind.
This páramitá of patience is the patience of receptivity to the truth concerning existence.
This páramitá of effort is the effort of perseverance in not focusing on body or mind.
This páramitá of meditation is the mind of integral sameness concerning all things.
This páramitá of wisdom is the total knowledge of the nature of all constituents of reality.

These are the páramitás which are dedicated completely to enlightenment.

p. 131

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

The paramita of giving ‘benefiting oneself’ is the giving of one
who is completely dedicated to achieving great transcendent enjoyment.

The paramita of morality ‘benefiting oneself’ is the moral
practice that leads to birth as a man or god in the happy states of existence.

The paramita of patience ‘benefiting oneself’ is the patience that,
due to the maturation of the attainment of patience,
causes one to have great beauty, a wonderful color, and great glory and power.

The paramita of effort ‘benefiting oneself’ is the effort of actively
examining everything by one’s own efforts and never depending on others for enlightenment.

The paramita of meditation ‘benefiting oneself’ is the meditation
of one who, because of the development of meditation,
does not come into a world between the kalpa of destruction and the seven kalpas of generation.

The paramita of wisdom ‘benefiting oneself’ is the wisdom of
one who does not look to outside beliefs, of one whose actions
of body, speech, and mind follow the truth.

These are the six paramitas that benefit oneself.

Glorious one, creator of all goodness, Mañjuśrī, his glorious eminence!Manjushri-namasamgiti

Could you possibly tell us the Sanskrit name of the 6th Buddha (the one after Maitreya)?

In the Tibetan tradition this is said to be variously Senge (Wyl. seng ge; Skt. Simha), Drukpa Senge, or Senge Namdrel. Seeing the original Sanskrit from the Bhadrakalpika Sutra would help clarify the words behind the Tibetan translations, as I'm not able to find either the Uchen or Wylie renderings, only the Anglicized phonetic spellings.

"The Sutras, Tantras, and Philosophical Scriptures are great in number. However life is short, and intelligence is limited, so it's hard to cover them completely. You may know a lot, but if you don't put it into practice, it's like dying of thirst on the shore of a great lake. Likewise, a common corpse is found in the bed of a great scholar." ~ Karma Chagme

Could you possibly tell us the Sanskrit name of the 6th Buddha (the one after Maitreya)?

In the Tibetan tradition this is said to be variously Senge (Wyl. seng ge; Skt. Simha), Drukpa Senge, or Senge Namdrel. Seeing the original Sanskrit from the Bhadrakalpika Sutra would help clarify the words behind the Tibetan translations, as I'm not able to find either the Uchen or Wylie renderings, only the Anglicized phonetic spellings.

It's Simha.

"The Guru is the Buddha, the Guru is the Dharma,
The Guru is the Sangha too,
The Guru is Śrī Heruka.
The All-Creating King is the Guru."
-- The Secret Assembly Tantra

Here's a dumb question, why kalpika in this context? Why not just kalpa?

It reminds me of Daśabhūmikasūtra, why bhūmika? Why not just bhūmi/bhūmyaḥ?

歸命本覺心法身常住妙法心蓮臺本來莊嚴三身徳三十七尊住心
城遠離因果法然具普門塵數諸三昧無邊徳海本圓滿還我頂禮心諸佛In reverence for the root gnosis of the heart, the dharmakāya,
for the ever present good law of the heart, the lotus terrace,
for the inborn adornment of the trikāya, the thirty-seven sages dwelling in the heart,
for that which is removed from seed and fruit, the upright key to the universal gate,
for all boundless concentrations, the sea of virtue, the root perfection,
I prostrate, bowing to the hearts of all Buddhas.胎藏金剛菩提心義略問答鈔, Treatise on the teaching of the gnostic heart of the womb and the diamond, T2397.1.470c5-8

Thank you, Norwegian. As it was pointed out to me by both a khenpo and a translator friend, Drukpa is most likely དྲུག་པ་ (drug pa), and thus སངས་རྒྱས་དྲུག་པ་སེངྒེ་ was erroneously read as "Buddha named Drukpa Senge" rather than the obvious "Sixth Buddha named Senge." Drukpa is ordinal, not part of the name.

Coëmgenu, I'm not sure why it's -kalpika rather than -kalpa, as I've not really studied Sanskrit in any formal capacity. I saw both, but -kalpika was far more common.

"The Sutras, Tantras, and Philosophical Scriptures are great in number. However life is short, and intelligence is limited, so it's hard to cover them completely. You may know a lot, but if you don't put it into practice, it's like dying of thirst on the shore of a great lake. Likewise, a common corpse is found in the bed of a great scholar." ~ Karma Chagme